Dish stacking cart

ABSTRACT

A dish cart includes a top with a slot for receiving a lift arm that may be lifted up through the slot to raise or lower dishes. Lobe openings emanating from the slot receive lobes of a lift paddle secured to the lift arm. The cart may define a gap below the top for permitting insertion of the lift paddle and the lift arm. The cart may be adjusted to receive differently sized dishes by means of rails of different sizes or adjustable vanes. A dish drop station includes the lift arm and lift paddle and a lift mechanism for raising and lower the lift arm. The dish drop station may include a cart present sensor and include a lock for retaining the cart. The controller may be programmed to the lower the lift arm to an unlock position that disengages the cart lock.

BACKGROUND Field of the Invention

This invention relates to carts and other systems for handling dishes.

Background of the Invention

Many restaurants serve patrons on reusable plates, bowls, silverware,and other serving dishes. Although this reduces the environmental impactof single-use plastic products, cleaning the dishes is a labor intensiveprocess.

What is needed is an improved approach for handling dishes for use inrestaurants and other food-service applications.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered limiting of its scope, the invention will be describedand explained with additional specificity and detail through use of theaccompanying drawings, in which:

FIG. 1 is an isometric view of a cart in accordance with an embodimentof the present invention;

FIG. 2 is an isometric view of a dish cart including an alternativeupper frame in accordance with an embodiment of the present invention;

FIG. 3 is an isometric view of a dish cart base for use with the upperframe of FIG. 2 in accordance with an embodiment of the presentinvention;

FIG. 4 is an isometric view of a rack cart in accordance with anembodiment of the present invention;

FIG. 5 is an isometric view of an alternative embodiment of a dish cartin accordance with an embodiment of the present invention;

FIG. 6 is a partial isometric view of the dish cart of FIG. 5;

FIG. 7 is an exploded view of an adjustable upper frame for a dish cartin accordance with an embodiment of the present invention;

FIG. 8 is an assembled isometric view of the dish cart of FIG. 7;

FIGS. 9A to 9C are partial isometric views of the dish cart of FIG. 7;

FIGS. 10A and 10B are cross-sectional views of the dish cart of FIG. 7;

FIGS. 11A and 11B are top views showing an example usage of the dishcart of FIG. 7;

FIGS. 12A and 12B are side views showing the example usage of the dishcart of FIG. 7;

FIG. 13 is an isometric view of a set of dish drop stations withcorresponding dish carts in accordance with an embodiment of the presentinvention;

FIG. 14 is a front isometric view of the dish drop station of FIG. 13;

FIG. 15 is a schematic diagram illustrating usage of a dish drop stationin accordance with an embodiment of the present invention;

FIG. 16 is an isometric view of a set dish drop stations according to analternative embodiment of the present invention;

FIG. 17 is an isometric view of a dish drop station having a lid inaccordance with an embodiment of the present invention;

FIG. 18 is an isometric view of the dish drop station of FIG. 18 havingthe lid open;

FIG. 19 is a top view of the dish drop station of FIG. 18;

FIG. 20 is a side view of a dish drop station showing various positionsof a lift arm in accordance with an embodiment of the present invention;

FIGS. 21A and 21B are side views of a dish drop station and dish cartshowing a manner of usage thereof in accordance with an embodiment ofthe present invention;

FIGS. 22 and 23 are front views of a lift mechanism for a dish dropstation in accordance with an embodiment of the present invention;

FIG. 24 is an isometric view of a cart lock mechanism of a dish dropstation in accordance with an embodiment of the present invention;

FIG. 25 is an isometric view of the cart lock mechanism of FIG. 24showing the cart lock mechanism in an open state in accordance with anembodiment of the present invention;

FIG. 26 is an isometric view of the cart lock mechanism of FIG. 24showing the cart lock mechanism in a locked state in accordance with anembodiment of the present invention;

FIGS. 27A to 27D are side views showing a method of operation of thecart lock mechanism of FIG. 24 in accordance with an embodiment of thepresent invention;

FIGS. 28A to 28C are isometric views illustrating operation of analternative embodiment of a cart lock mechanism in accordance with anembodiment of the present invention;

FIG. 29 is a side view illustrating an inductive sensor and magneticdetent in accordance with an embodiment of the present invention; and

FIG. 30 is a schematic block diagram of a control system for a dish dropstation in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

Referring to FIG. 1, a cart 10 may be understood with respect to alongitudinal direction 12 a, vertical direction 12 b, and horizontaldirection 12 c that are all mutually perpendicular to each other.

The cart 10 includes a handle 14 and a base 16. The handle 14 includesvertical bars 18 that extend upwardly from the base 16 in the verticaldirection 12 b, though they may also be angled such that they extendoutwardly from a point of attachment to the base in one or both of thelongitudinal and horizontal directions 12 a, 12 c. A horizontal bar 20secures to tops of the vertical bars 18 and is preferably at aconvenient height to be grasped and pushed by a user. In the illustratedembodiment, the bars 18, 20 are one monolithic tube bent into theillustrated shape.

The base 16 may include a frame composed of frame members 22 a, 22 b, 22c, 22 d such that each frame member has the long dimension thereofsubstantially (within 5 degrees) parallel to one side of a quadrilateralshape, such as a square or rectangle. For example, frame members 22 aand 22 c are offset from one another along the longitudinal direction 12a and have the long dimension thereof oriented substantially parallel tothe horizontal direction 12 c. Likewise, frame members 22 b and 22 d areoffset from one another along the horizontal direction 12 c and have thelong dimension thereof oriented substantially parallel to thelongitudinal direction 12 a.

As shown, the frame member 22 a at a front of the base 16 is bent orcutaway at a middle portion thereof such that an upper surface of amiddle portion of frame member 22 a is below upper surfaces of the otherframe members 22 a, 22 b, 22 c. As discussed below, this bent or cutawaymiddle portion enables insertion of a lift arm for supporting dishes orracks stacked onto the cart 10 according to the approach describedherein.

In the illustrated embodiment, corner piece 24 a is secured to framemember 22 a and 22 b, corner piece 24 b is secured to frame members 22 band 22 c, corner piece 24 c is secured to frame members 22 c and 22 d,and corner piece 34 d is secured to frame members 22 d and 22 a. In someembodiments, the corner pieces 24 a-24 d for part of the frame such thatthe frame members 22 a-22 d are secured to one another exclusively dueto their securement to the corner pieces 24 a-24 d. The corner pieces 24a-24 d define upper surfaces that are substantially parallel to thelongitudinal and horizontal directions 12 a, 12 c.

The corner pieces 24 a-24 d may define structures for securing a topplate or other platform to the base 16 for supporting stacked items suchas dishes, dish racks, or other stackable items. In the illustratedembodiment, the structures are posts 26 that may insert withincorresponding openings in a platform placed over the base 16. The posts26 may include openings for receiving fasteners for securing theplatform to the base 16. In other embodiments, the corner pieces 24 a-24d include openings for receiving fasteners and the posts 26 are omitted.

In the illustrated embodiment, the base 16 further includes a lowerframe 28 secured to the frame members 22 a-22 d. The lower frame 28 maydefine rails configured to removably support a drip pan positioned underthe frame formed by frame members 22 a-22 d.

Wheels 30 a-30 d may secure to the corner pieces 24 c-24 d. Fourth wheel(see, e.g., wheel 30 a in FIG. 6) secures to corner piece 24 a in a likemanner. In the illustrated embodiment, the wheels 30 may be casterwheels that are able to swivel about an axis substantially parallel tothe vertical direction 12 b relative to the structure to which they aremounted in addition to rolling along a horizontal support surface. Inthe illustrated embodiment, wheels 30 d and the wheel secured to cornerpiece 24 a (see 30 a in FIG. 6) are fixed such that their axes ofrotation are substantially parallel to the horizontal direction 12 c. Incontrast, wheels 30 b and 30 c are swivel-mounted to the corner pieces24 b, 24 c. In the illustrated embodiment, wheels 30 b, 30 c furtherinclude locks 32 that may be selectively engaged by a user to hinderrotation of the wheels 30 b, 30 c. In other embodiments, locks 32 areadditionally or alternatively coupled to the wheels 30 a, 30 d. In stillother embodiments, wheels 30 a, 30 d include locks 32 and have a fixedorientation whereas the wheels 30 b, 30 c are free to swivel and lacklocks 32

In some embodiments, bumpers 34 made of plastic, rubber, or otherresilient material are mounted to the corner pieces 24 a-24 d, e.g. theoutward facing two sides of the corner pieces 24 a-24 d in order toreduce damage caused by impacts.

Referring to FIGS. 2 and 3, in some embodiments a cart 10 may beaugmented with additional structures to function as a dish cart. InFIGS. 2 and 3, the dish cart 10 includes a handle 14 having theillustrated configuration, including four vertical posts 40 a-40 d thatextend upwardly from the base 16 substantially parallel to the verticaldirection 12 b. The posts 40 a-40 d may be arranged in a quadrilateralshape, i.e. such that central axes of the posts 40 a-40 d are positionedon corners of a quadrilateral shape such as a square or rectangle. Insome embodiments, the posts 40 a-40 d are at corners of a parallelogramto facilitate proper alignment of the top and bottom. In someembodiments, only three posts are used, rather than 4.

The handle 14 may further include one or more bars 42 a-42 c that extendsubstantially parallel to either the longitudinal direction 12 a or thehorizontal direction 12 c. For example, in the illustrated embodiment,bar 42 a and is secured to vertical posts 40 a and 40 b and has the longdimension thereof substantially parallel to the longitudinal direction12 a. Likewise, bar 42 c has its long dimension substantially parallelto the longitudinal direction is secured to vertical posts 40 c and 40d. The bar 42 b is connected to the bars 42 a and 42 c and provides ahandle at a convenient height for pushing the cart 10. In theillustrated embodiment the posts 40 a-40 d and bars 42 a-42 c are allembodied as hollow tubes made of a sufficiently strong material such assteel or aluminum. In the illustrated embodiment, bars 42 a-42 c andvertical posts 40 a, 40 d are made of a one tube bent in the illustratedshape.

In the embodiment of FIGS. 2 and 3, the handle 14 secures to the base 16by means of tubes 44 a-44 d that fit over corresponding posts 46 a-46 dsecured to the base 16. In some embodiments, no further fastening isused, i.e. the weight of the handle 14 and the length of the tubes 44a-44 d and posts 46 a-46 d is relied upon to prevent accidental removal.Posts 46 a-46 d may secure to the base 16 using the posts 26 or in placeof the posts 46 a-46 d.

In the embodiment of FIGS. 2 and 3, rails 48 a-48 d secure to some orall of the posts 40 a-40 d and extend radially inwardly to a commoncentral point such that there is a radial extent 50 of each rail 48 a-48d. The radial extent 50 of the rails 48 a-48 d is chosen to define thediameter of items that will fit stacked on the base among the rails 48a-48 d. For example, a cart 10 may come with multiple sets of rails,each set including four rails 48 a-48 d that have extents 50 defining adiameter when secured to the posts 40 a-40 d, the diameter defined byeach set being different. In this manner, by installing different setsof rails, the cart may be configured to stack different sizes of dishes,e.g., dinner plates, salad plates, dessert plates, bowls, etc.

In the illustrated embodiment, each rail 48 a-48 d mounts to itscorresponding post 40 a-40 d by means of fasteners 52, such as screws,bolts, or other type of fastening means. The rails 48 a-48 d preferablydefine countersunk apertures for receiving such fasteners 52 in suchthat heads of screws or bolts do not contact stacked items on the cart10.

In the illustrated embodiment, the posts 40 a-40 d and tubes 44 a-44 dare fastened to a plate 54, such as by means of welding, screws, bolts,or other fastening means. For example, the plate 54 may be made of thesame material (steel, aluminum) as the posts 40 a-40 d and the tubes 44a-44 d. The plate 54 may define apertures aligned with channels definedby the tubes 44 a-44 d such that the posts 46 a-46 d may pass throughthe plate 54 to insert within the tubes 44 a-44 d.

In some embodiments, a pad 56 secures to the plate 54 to provide asofter support surface for dishes stacked on the base 16. For example,the pad 56 may be embodied as a circular plastic piece fastened to theplate 54 by means of screw, adhesive, clips, or some other fasteningmeans. As is apparent in FIG. 2, the pad 56 defines various openings 58.The plate 56 defines corresponding openings aligned with the openings58. The openings 58 may be lobe openings 58 having a size configured toallow a multi-lobed lift paddle to pass through the pad 56 and plate 54,as will be discussed in greater detail below. The pad 56 may furtherdefine a slot 60 aligned with a corresponding slot 62 in the plate 54for permitting through passage of a lift arm secured to the lift paddle.As is apparent in FIG. 2, the slot 60 extends completely to the edge ofthe pad 56 and the slot 62 in the plate 54 extends completely to thefront edge of the plate 54. The slot 62 extends to the edge of the plate54 and may be positioned over the frame member 22 a that includes thebent or cutaway portion for receiving the lift paddle and lift arm. Inparticular, a gap may be defined between the bottom surface of the plate54 and the bent or cutaway portion of the frame member 22 a forreceiving the lift paddle and lift arm.

In some embodiments, the pad 56 further defines grooves 64 extendingradially inward to the openings 58 and/or slot 60. In this manner,material and fluid from dishes stacked in the cart is guided to theopenings 58 and/or slot 60.

Referring specifically to FIG. 3, in some embodiments, the base 16includes a lower plate 66 mounted to the frame members 22 a-22 d and/orcorner pieces 24 a-24 d or used in place of the frame members 22 a-22 dand corner pieces 24 a-24 d. The posts 46 a-46 d may be welded orotherwise fastened to the lower plate 66. As is apparent, an innerportion of the lower plate 66 defines an indentation or depression 68that extends to the front edge of the base 16 over the frame member 22 asuch that the lift paddle and lift arm may insert between theindentation 68 and plate 54 and subsequently be lifted up through theslots 60, 62 and lobe openings 58 as described in greater detail below.The lift paddle and lift arm may likewise pass down through the slots60, 62 and lobe openings 58 and the lift paddle and the lift arm may bewithdrawn from the gap between the plate 54 and indentation 68 as isalso described in greater detail below.

Note that in the illustrated embodiment, the base 16 further definesapertures 72 in frame member 22 c for receiving a handle 14 having theform shown in FIG. 1. In other embodiments, such apertures 72 may beomitted.

FIG. 4 illustrates a rack cart 80 that may be modified relative to thecart 10 of FIG. 1 to function as a rack cart as described below. Inother instances, the cart 10 of FIG. 1 may be used as a rack cartwithout further modification. In the embodiment of FIG. 4, a plate 82may be mounted to the frame members 22 a-22 d and/or corner pieces 24a-24 c. The plate 82 includes lobe openings 84 sized to permit passagetherethrough of the lobes of a lift paddle. A slot 86 likewise extendsfrom the front edge of the plate over the frame member 22 a and connectsto the lobe openings 84 such that the lift paddle and lift arm may passthrough the lobe openings 84 and slot 86.

In the illustrated embodiment, corner projections 88 a-88 d are locatedat the corners of the plate 82, which is quadrilateral in shape but forrounding at the corners, with sides of the quadrilateral shape beingparallel to one of the longitudinal direction 12 a and the horizontaldirection 12 c. Each corner projections 88 a-88 d extend from onerounded corner of the quadrilateral shape and partially along twoadjoining sides of the quadrilateral shape and likewise extend upwardlyalong the vertical direction 12 b. The corner projections 88 a-88 d aresized to fit within corresponding recesses in a dish rack according toany shape known in the art such that the rack cart 80 is enabled tosecurely stack dish racks, glass racks, trays, or other types of racksknown in the food service industry.

FIGS. 5 and 6 illustrate an alternative embodiment of a dish cart 10. Inparticular, in the illustrated embodiment, the top plate 54 is fastenedto the corner pieces 24 a-24 d by means of bolts 90, such as by securingto the posts 26 on the corner pieces 24 a-24 d or openings for receivingthe bolts 90 formed on another portion of the base 16.

FIG. 5 further illustrates an alternative approach for securing therails 48 a-48 d to the posts 40 a-40 d. In particular, each post mayhave one or more flanges 92 secured thereto and extending radiallyinwardly into the cart 10. The rails 48 a-48 d may then secure to theseflanges 92 by means of bolts, screws, or some other fastening means. Asfor the embodiment of FIGS. 2 and 3, different sets of rails 48 a-48 dmay secure to the flanges 92 in order to adjust the size of dishes thatwill fit among the rails 48 a-48 d.

In the embodiment of FIG. 5, a screen 94, which may be a solid orperforated piece of material, such as metal or plastic, secures to theposts 40 b, 40 c such that the screen is secured to the cart 10 oppositethe front edge of the cart 10. Accordingly, the screen 94 may blockscattering of material out of the back of the cart 10 during use. Thescreen may be detachable and may be one of multiple screens havingmultiple colors such that the color of the screen attached to a cartindicates the contents of the cart, e.g., size of dishes loaded or ableto be loaded into cart or a state of the dishes in the cart (clean ordirty)

In the embodiment of FIG. 5, metal lugs 96 secure to one or both of theposts 40 a, 40 d such that the metal lugs extend forwardly from theposts 40 a-40 d outwardly from the front of the cart 10 andsubstantially parallel to the longitudinal direction 12 a. The metallugs 96 may further have a face substantially parallel to the verticaland horizontal directions 12 b, 12 c. As discussed below with respect toFIG. 29, the metal lugs may facilitate securement of the cart by amagnetic detent.

Referring specifically to FIG. 6, the lower plate 66 may have variousconfigurations. In the illustrated embodiment, the indentation 68 ordepression in the lower plate 66 defines various slits 98 to facilitatedrainage, such as slits oriented substantially parallel to thehorizontal direction 12 c.

Note further that in some embodiments where the handle 14, such as theposts 40 a-40 d and horizontal bars 42 a-42 c are secured (e.g., welded)to the top plate 54, the top plate 54 may function as the frame for thebase 16 such that frame members 22 a-22 d are omitted and the cornerpieces 24 a-24 d with the wheels 30 a-30 d secure only to the plate 54.Alternatively or additionally, the lower plate 66 may secure to thecorner pieces 24 a-24 d, such as interposed between the upper plate 54and the corner pieces 24 a-24 d.

As for other embodiments, the upper plate 54 of FIG. 6 includes lobeopenings 58 for receiving a lift paddle and a slot 62 extendingcompletely to the front edge of the top plate 54. Various configurationsfor a lift paddle are possible, such as a three lobe design or a fourlobe design. In the embodiment of FIG. 6, a four lobe design is usedthat has four-fold symmetry, each lobe being rotated 90 degrees relativeto an adjacent lobe. Accordingly, only three lobe openings 58 are usedwith the fourth lobe being aligned with the slot 62 and passingtherethrough along with the lift arm to which the lift paddle issecured.

In other embodiments, such as shown in FIG. 4, the lift paddle has threelobes with three-fold symmetry such that each arm is rotated 120 degreesrelative to the other lobes. As shown in FIG. 4, one lobe opening 84 isoriented parallel to the slot 86. The three-lobe design may also be usedfor the carts 10 of FIGS. 1-3, 5, and 6 as well.

The embodiment of FIGS. 5 and 6 and any of the embodiments of FIGS. 1-4may further include structures for locking the cart 10 into a dish dropstation as discussed in greater detail below. In the illustratedembodiment, the upper plate 54 includes apertures 100 for receiving acart lock, the aperture 100 being positioned over the gap defined by theupper plate 54 and the lower plate 66 and being located closer to thefront edge 100 than any other edge of the plate 54. Correspondingapertures 100 may be positioned at the front edge of the base of any ofthe embodiments of FIGS. 1-4 as well. In some embodiments, only a singleaperture 100 is used.

In some embodiments, the plate 504 includes an indentation 102, such asfor providing clearance for a drive mechanism of a lift arm according tothe embodiments of dish drop stations described below.

Dish carts according to the embodiments disclosed herein may furtherinclude structures such as hooks and receptacles for hooks that enabledish carts to be hooked to one another to facilitate transportation by asingle person as a group.

Referring to FIG. 7, a cart 10 may be embodied as a dish cart includingan adjustment assembly 110. For example, the adjustment assembly 110 maybe used to modify the dish cart 10 to stack dishes of different sizes.Accordingly, the adjustment assembly 110 may take the place ofdifferently sized sets of rails 48 a-48 d. The adjustment assembly 110may be used to adapt cart 10 such as that shown in FIG. 1 that lacks thevertical posts 40 a-40 d. Alternatively, the vertical posts 40 a-40 d ofa cart 10 as shown in FIGS. 2-3 and 5-6 may provide room for theadjustment assembly 110.

The adjustment assembly 110 may include a plurality of vanes 112 a-112 cthat are rotatable about axes substantially parallel to the verticaldirection 12 b. In this manner, the area within the vanes 112 a-112 cthat is not obstructed by the vanes 112 a-112 c may be varied in orderto accommodate dishes of different sizes.

In the illustrated embodiment, each vane 112 a-112 c may include a firstrod 114 that is rotatably pinned to the base 16 and a second rod 116that is coupled to the other rods 116 such that rotation of one vane 112a-112 c about its rod 114 will cause the other rods 112 a-112 c torotate about their corresponding rods 114.

The vanes 112 a-112 c may further include a third rod 118 at an inneredge of the vane 112 a-112 c in order to provide rigidity to the vanes112 a-112 c. In the illustrated embodiment, the vanes 112 a-112 c eachinclude a first sleeve 120 receiving the first rod 114, a second sleeve122 receiving the second rod 116, and a third sleeve 124 receiving thethird rod 118.

The vanes 112 a-112 c may further include a web 126 extending betweenthe first sleeve 120 and the second sleeve 122 and a web 128 extendingbetween the first sleeve 120 and the third sleeve 124. As is apparent inFIG. 7, the sleeves 120-124 and the webs 126, 128 may be monolithicallyformed with one another such as by co-molding or extrusion as a singlemember. As is also apparent in FIG. 7, the sleeves 120-124 and the webs126, 128 have a substantially (within 2 mm) constant cross section alongthe vertical direction 12 b in the illustrated embodiment.

In use, the web 128 extends inwardly with the amount by which it extendsinwardly varying as the vanes 112 a-112 c are rotated. The presence ofthe third rod 118 resists bending of the inner edge of the web 128. Asis apparent, the web 128 is curved such that a concave inner surface ofthe web 128 faces toward a center of the base when the web 128 ispivoted outwardly to accommodate large dishes, the web 128 will notinterfere with dishes stacked among the vanes 112 a-112 c. In someembodiments, the web 128 does not contact dishes at any of its possibleorientations. Instead, dishes are only contacted by the sleeve 124 inwhich the rod 118 is inserted.

In the illustrated embodiment, the first rods 114 insert withinapertures 130 formed in the top plate 54. For example, the apertures 130may be distributed at 120 degree intervals about a point on the plate 54such that one aperture 130 is substantially (within 1 cm) aligned with acenter of the slot 62 along the horizontal direction 12 c but positionedcloser to the rear edge than to the front edge of the base 16 such theslot 62 does not intersect this aperture 130.

As is apparent in FIG. 7 each rod 114 protrude both above and below thewebs 126, 128 of the vane 112 a-112 c in which it is located. In someembodiments, the portions of the rod 114 protruding above and below thewebs 126, 128 are a single rod whereas in other embodiments they areseparate rods.

In the illustrated embodiment, the second rod 116 protrudes only belowthe webs 126, 128 and may extend along the entire extent of the secondsleeve 122 or only partially through the sleeve 122.

The third rod 118 may either not protrude from the third sleeve 124,protrude both above and below the third sleeve 124, or protrude only oneof above and below the third sleeve 124. In the illustrated embodiments,portions of the third rod 118 that protrude above or below the thirdsleeve 124 are covered with caps made of a material that is softer thanthe metal (e.g., steel) of which the rods 114-118 may be formed. Forexample, the caps may be made of a resilient polymer or rubber to avoiddamaging dishes placed among the vanes 112 a-112 c. The caps maylikewise prevent insertion of the third rod 118 into the aperturesintended to receive the first or third rod.

Note further that the first rod 114 extends below the first sleeve 120 agreater extent than second third 116 extends below the second sleeve 122in the illustrated embodiment. In this manner, when the first rod 114 ofa vane 112 a-112 c is inserted in an aperture 130, the downwardprotruding portion of the second rod 116 will remain above the bottomplate 54 and the pad 56 such that it does not hinder pivoting of thevane 112 a-112 c.

Referring to FIG. 8, while still referring to FIG. 7, the vanes 112a-112 b may engage partial circular members 132, 134. Each of thepartial circular members is a partial ring with the gap in the ringfacing the front edge of the base 16. In this manner, passage of thelift arm through the gap is permitted.

In the illustrated embodiment, the upper partial circular member 132 ispivotally mounted to the handle 14, such as to a horizontal rod 136extending between the vertical bars 18 of the handle 14. This mayfacilitate disassembly of the adjustment assembly for cleaning.

The lower partial circular member 134 rests on the top plate 54 and maybe positioned outside of the outer perimeter of the pad 56. The upperpartial circular member 132 may include apertures 138 and the lowerpartial circular member 134 may include apertures 140. The apertures 140may be positioned aligned with one another and with the apertures 130 inthe plate 54 such that the first rod 114 of each vane 112 a-112 cinserts within one of the apertures 130, one of the apertures 138, andone of the apertures 140 when positioned substantially parallel to thevertical direction 12 b.

As is apparent in FIG. 8, the apertures 140 are slots such that thefirst rod 114 is permitted to both slide and rotate within the slots. Insome embodiments, the apertures 140 is omitted and the inner diameter ofthe lower partial circular member 134 is made sufficiently large that itdoes not interfere with insertion of the first rods 114 into theapertures 130. In contrast, the apertures 138 in the upper partialcircular member 132 may permit rotation but not significant (e.g.,larger than 2 mm) of translational movement.

The lower partial circular member 134 may further define apertures 142that receive the second rods 116 of the vanes 112 a-112 c. In theillustrated embodiment, the apertures 142 are notches that extendpartially radially inwardly across the radial extent of the lowerpartial circular member 134, e.g. inwardly from an outer circumferenceof the lower partial circular member 134 partially across the lowerpartial circular member 134 toward a center of curvature defined by thelower partial circular member.

The apertures 142 permit rotation of the second rods 116 but do notpermit significant translational movement. In this manner, when thelower partial circular member 134 is rotated, all of the second rods 116rotate with it about the first rods 116 in the apertures 130 therebyresulting in simultaneous movement of the vanes 112 a-112 c subject toflexing and any non-significant translational movement relative to thelower partial circular member 134 coupling the vanes 112 a-112 c to oneanother.

In some embodiments, the upper partial circular member 132 may definetwo notches 144 (only one being visible in FIGS. 7 and 8) protrudingpartially radially outwardly from the inner diameter of the member 132and partially across the radial extent of the member 132. The notches144 are positioned to receive the protruding ends of the third rods 118when the vanes 112 a-112 b are pivoted such that two of the third rods118 contact the member 132. In this manner, the size of dishes that maybe positioned among the vanes 112 a-112 c is slightly increased. Notethat the third rod 118 of vane 112 c may extend into the gap in theupper partial circular member 132 such that a third notch 144 is notneeded to achieve this benefit.

FIG. 7 further shows a drip pan 146. The drip pan 146 may mount to thebase, such as below the lower plate 66 in order to catch material thatdrips down through the plates 54, 66. The drip pan 146 may mount to thelower plate 66 by means of rails supporting edges of the drip pan 146,clips, or other removable fastening means.

FIGS. 9A to 9C illustrate the process of adjusting the adjustmentassembly 110. In the illustrated embodiment, the lower partial circularmember 134 includes a plurality of edge notches 148. In the illustratedembodiment, the notches 148 are formed on the top and outer edge of thelower partial circular member 134 and include two sets of notches 148.

The notches 148 may engage one or more lock arms 150 that are pivotallymounted to the base 16, such as to the lower plate 54, frame member 22c, or other component of the base 16. The lock arms 150 may be springloaded such that they are biased into engagement with the notches 148. Astep arm 152 may be secured to the lock arms 150 such that pressingdownwardly on the step arm 152 will result in the lock arms 150 pivotingout of engagement with the notches 148.

In use, a user presses (e.g., steps) on the step arm 152 to disengagethe lock arms 150 with the vanes 112 a-112 c in a first orientation asshown in FIG. 9A. The user then rotates the vanes 112 a-112 c to adifferent orientation as shown in FIG. 9B. The user then releases thestep arm 152, which permits the lock arms 150 to engage with a differentpair of notches 148 corresponding to the current position of the vanes112 a-112 c as shown in FIG. 9C. In the illustrated embodiment, each setof notches 148—includes three notches 148 such that the vanes 112 a-112c may be locked in three different positions.

FIGS. 10A and 10B provide further illustration of the adjustment of thevanes 112 a-112 c. FIG. 10A illustrates the locking arms 150 in a firstpair of notches 148 and the third rods 118 positioned as shown such thata first diameter D1 of dishes will fit among the vanes 112 a-112 c. FIG.10B illustrates the locking arms 150 in a second set of notches 148 dueto rotation of the lower partial circular member 134 and the third rods118 positioned further inward as a result of the adjustment such thatonly dishes smaller than a second diameter D2, that is smaller than thefirst diameter D1, will fit among the vanes 112 a-112 c.

In particular, the innermost points of the vanes 112 a-112 c may besubstantially equidistant (e.g., equidistance being within 2 cm frombeing equal distances) from a first point, e.g. a center of the plate 56due to their coupling by the partial circular members 132, 134. Thisequal distance may then be varied by rotating the vanes 112 a-112 cusing the lower partial circular member 134. Note further that in someembodiments, the vanes 112 a-112 c are limited such that they cannotobstruct the first point, e.g., the center of the plate 56. This may beachieved by sizing of the openings 140 that limit how much the lowerpartial circular member 134 may rotate. In some embodiments, the vanes112 a-112 c are limited such that they cannot obstruct movement of thelift arm and lift paddle along the length of the vanes 112 a-112 c.

FIGS. 11A and 11B and corresponding FIGS. 12A and 12B illustrate anexample use of the adjustment assembly 110. In the illustratedembodiment, an interior 160 of a dish drop, such as a dish dropdescribed according to the embodiments below, includes a block 162,flange, or other structure that is positioned to engage the lowerpartial circular member 134. A hook 164 or other structure is positionedto urge the step arm 152 downward when the base 16 is urged into theinterior 160.

In particular, as shown in FIGS. 11A and 12A, the base 16 may be urgedinto the interior 160. The block 162 then contacts the lower partialcircular member 134 as the hook 164 engages the step arm 164 and urgesit downwardly, disengaging the lock arms 150 from the notches 148 andpermitting the block 162 to rotate the lower partial circular member134, as shown in FIGS. 11B and 12B. The block 162 then maintains thelower partial circular member 134 in this orientation. Removal of thebase 16 from the interior 16 may be resisted by a cart lock engaging theaperture 100, such as a cart lock according to any of the embodimentsdescribed below with respect to FIGS. 24-28C.

FIGS. 11A-12B illustrate just one example of how the adjustment assembly110 may be adjusted. In other embodiments, a knob or handle is securedto one of the rods 114, 116, 118 of one of the vanes and can be rotatedby a user to adjust the adjustment assembly 110. The knob may beremovable to permit disassembly. For example, the knob may removablysecure to a portion of a rod 114, 116, 118 protruding above the upperpartial circular member 132. In some embodiments, there is one and onlyone knob secured to one of the rods 114, 116, 118.

Referring to FIG. 13, a dish drop 170 may include one or more dish dropstations 172 a-172 d that are each sized and configured to receive acart 10 according to any of the foregoing embodiments. In theillustrated configuration, the dish carts 10 are according to theembodiment of FIGS. 7 through 10B.

The dish drop 170 may include a single top wall 174 for all of thestations 172 a-172 d or separate top walls 174 for each station 172a-172 d. The top wall 714 over each station 172 a-172 d includes anopening 176 for receiving dishes that stack within dish carts 10positioned within the stations 172 a-172 d. In some embodiments, eachstation 172 a-172 d includes a collar 178 that protrudes upwardly fromthe top wall 174 and partially or completely surrounds the opening 176of the station 172 a-172 d. The collar 178 may house electronics such asan antenna for transmitting a state of the station 172 a-172 d, sensorsfor detecting a height of items stacked in the station 172 a-172 d, orother components. Accordingly, the collar 178 may be formed of plasticor other polymer that permits transmitted signals to pass therethrough.

In the illustrated embodiment, each station 172 a-172 d includes abutton 180 placed on the top wall 174 for each station 172 a-172 d orpositioned elsewhere, such as an inner wall 192 (facing away from theviewer in FIG. 13). The button 180 may be a mechanical button, touchscreen interface, switch, or any other type of structure able to receiveuser interaction. As discussed below, the button 180 may instruct acontroller to lower a lift arm and lift paddle to an unlock positionsuch that cart 10 at the station 172 a-172 d may be removed.

FIG. 14 illustrates an individual dish drop station 172 a-172 d. As isapparent, the station 172 a-172 d may include side walls 182 or a sideframe 182 having guides 184 mounted thereto. The guides 184 facilitateinsertion of the cart 10 into the station 172 a-172 d. At an entrance ofthe dish drop station 172 a-172 d, the guides 184 may be flared, such asby means of a bevel 186 or chamfer that urges the cart 10 into alignmentwith the guides 184 in cases where it is slightly misaligned as shown inFIG. 15.

FIG. 14 further shows the lift arm 188 and lift paddle 190 that operatein conjunction with features of the cart 10 intended for cooperationwith the lift arm 188 and lift paddle 190 as described above. The liftarm 188 protrudes from an inner wall 192 of the station 172 a-172 d andmoves along the inner wall 192 substantially parallel the verticaldirection 12 b. The inner wall 192 may define a slit 194 substantiallyparallel to the vertical direction 12 b along which the arm 188 movesand through which the arm 188 protrudes. The edges of the slit 194 maybe lined with a flexible material such that the flexible materialsubstantially completely (e.g., 90 percent) covers the slit 194 butdeforms to permit movement of the arm 188 as it passes along theflexible material.

In the illustrated embodiment, the lift paddle 190 has three lobes 196.However, a lift paddle 190 with four lobes may be used with a cart 10configured to cooperate therewith as described above.

FIG. 14 further illustrates a cart lock 198 that may engage the aperture100 in the plate 54 of a dish cart 10 according to the embodimentsdisclosed above. As noted above, there may be two apertures 100 in someembodiments of the dish cart 10. Accordingly, some embodiments of thestations 172 a-172 d may further include two cart locks 198. Functioningof the cart locks 198 and different embodiments thereof are described ingreater detail below.

In the illustrated embodiment, the collar 178 includes stack heightsensors 200 a, 200 b. In other embodiments, these sensors 200 a, 200 bmay be incorporated into the opening 176. The stack height sensors 200a, 200 b may be offset from one another in the vertical direction 12 b.For example, stack height sensor 200 a may be an upper height sensor andsensor 200 b may be a lower height sensor that is positioned slightlybelow sensor 200 a in the vertical direction 12 b (e.g., on the order of3 to 15 mm or 0.5 to 2 times a thickness of a dish stacked using thestation 172 a-172 b).

In operation, a controller drives an actuator coupled to the lift arm188 according to outputs of the sensors 200 a, 200 b. For example:

-   -   (A) If sensor 200 b is obstructed and sensor 200 a is not, do        nothing;    -   (B) If both sensors 200 a, 200 b are obstructed, lower the lift        arm 188 until sensor 200 a is not obstructed but sensor 200 b is        obstructed; and    -   (C) If both sensors 200 a, 200 b are not obstructed, raise the        lift arm 188 until sensor 200 a is not obstructed but sensor 200        b is obstructed.

Case (B) occurs when items are being added to a dish cart 10 at thestation 172 a-172 d, which may occur when collecting dirty dishes orloading a dish cart 10 with clean dishes. For example, a dish dropstation 172 a-172 d may be placed next to a dish washing machine forloading of clean dishes from the dish washing machine into carts 10.

Case (C) occurs when items are being removed from a dish cart 10 at thestation, which may occur when removing dirty dishes for cleaning or whenremoving clean dishes for serving food on them. For example, a dish dropstation 172 a-172 d may be placed next to a conveyor belt such that aworker may remove dishes from the dish drop station 172 a-172 d andplace them on the conveyor belt for subsequent processing such asrinsing and loading into dish racks.

In another example, the cart 10 may be substituted with a rack cart 80.Accordingly, a rack cart station may have the structures of a dish dropstation 172 a-172 d sized to receive dish racks and the top plate 174and collar 178 may be omitted such that racks may be placed on a rackcart. However, stack height sensors 200 a, 200 b may be retained, suchas mounted to the side walls 182 or inner wall 194. Accordingly, in caseC, racks may be removed from the rack cart station for filling withdishes while the lift arm 188 is raised such that the lower stack heightsensor 200 b becomes obstructed and the upper stack height sensor 200 abecomes/stays unobstructed. For example, a rack cart station and a dishdrop station 172 a-172 d may be used simultaneously according to case C:dishes are removed from the dish drop station 172 a-172 d, rinsed, andloaded into dish racks. As dish racks are filled, new dish racks areretrieved from the rack cart station. Loaded dish racks may then beloaded into a dish washer. Loaded dish racks may be placed on a conveyorbelt feeding through the dish washer.

The sensors 200 a, 200 b may be embodied as break beam sensors, optical(e.g., camera) sensors, or any other sensor for detecting presence orabsence of an item within a region around the sensor. The sensors 200 a,200 b may further be embodied as distance sensors that can sense adistance to a dish positioned in front of the sensors 200 a, 200 b. Inthis manner, the sensors 200 a, 200 b can detect both whether an objectis detecting it but also whether it is in fact a dish. For example, anappropriately sized dish would have an edge closer to the sensor 200 athan another object, such as flatware or other object. A controller maytherefore detect non-dishes or dishes that are too small and rejectionthem, e.g. refuse to lower the list arm 188 when a non-dish or a dishthat is too small as determined according to the output of the distancesensors 200 a-200 b is detected.

FIG. 16 illustrates alternative embodiments for some of the features ofa dish drop 170. In the illustrated embodiment, the sidewalls 182 ofeach dish drop station 172 a-172 d include two pairs of guides 184 thatare offset from one another along the vertical direction to facilitateinsertion of carts into the dish drop stations 172 a-172 d. The liftpaddle 190 may have the four-lobe design as discussed above. However,the three-lobe design may also be used.

The dish drop stations 172 a-172 d may each include a front housing 208positioned in front of the inner wall 192, such that the inner wall 192is positioned between the side walls 182 and the front housing 208. Thefront housing 208 may house a drive motor for driving the lift arm 188and electronic circuits forming the controller for controlling operationof the dish drop station 172 a-172 d. The front housing 208, andpossibly the sidewalls 182, of adjacent dish drop stations 172 a-172 dmay be fastened, e.g. bolted, to one another. Sealant or seals may beplaced between the front housings 208 of adjacent dish drop stations 172a-172 d to prevent entry of contaminants into the front housings 208.

In some embodiments, an emergency stop button 210 is mounted to a sideof the front housing 208 of one of the drop stations 172 a-172 d, e.g.one of the drop stations on the ends of the series of drop stations 172a-172 d, the rightmost dish drop station 172 d in the illustratedembodiment. A restart button 212 may also be mounted to the side of thefront housing 208 of one of the drop stations 172 a, 172 d on the ends.The restart button 212 may be coupled to the controller and, whenpressed, may instruct the controller to restart operation of the dropstations 172 a-172 d following pressing of the emergency stop button210. In the illustrated example, this is the same station 172 d to whichthe emergency stop button 210 is mounted.

One or more wires 214 may couple the emergency stop button 210 to thecontrollers of the dish drop stations 172 a-172 d for invoking anemergency stop of all of the dish drop stations 172 a-172 d. Likewise,one or more wires 216 may couple the reset button 212 to the controllersof the dish drop stations 172 a-172 d for invoking resetting the dishdrop stations 172 a-172 d following pushing of the emergency stop button210.

In the illustrated embodiment, one of the dish drop stations 172 a-172 dincludes a power supply 218 that may be embodied as an adaptor or otherinterface to an electrical outlet. The power supply 218 may also be arechargeable battery. In the illustrated embodiment, the power supply218 is positioned in the dish drop station 172 a that is on an oppositeend of the series of dish drop stations 172 a-172 d from the dish dropstation 172 d to which the emergency stop button 210 and the powerbutton 212 are mounted.

The lines 214, 216 may therefore include lines coupling power to thedish drop stations 172 a-172 d from the power supply 218 and linescoupling control signals to the dish drop stations 172 a-172 d from thebuttons 210, 212.

In the illustrated embodiment, each side of the rear housing (left andright in the illustrated example, i.e., substantially parallel to thevertical and longitudinal directions 12 a, 12 b) includes an opening.The openings on the exposed sides of the housing 208 of the dish dropstations 172 a and 172 d on the ends are closed by a cover 220 securedover the opening. The emergency stop button 210 and power button 212 maybe mounted on this cover 220. The cover 220 on the left side of dishdrop station 172 a is present but not visible in the illustratedexample. The cover 220 on the left side may be identical but may lackthe emergency stop button 210 and power button 212. For example, anelectrical plug for interfacing with the power supply 218 may beaccessible through the cover 220 on the dish drop station 172 a, such asby means of an electrical cord protruding through the cover 220 andcoupled to the power supply 218.

The intermediate dish drop stations 172 b-172 c that are not on the endsmay lack covers 220. Likewise, inner facing surfaces of the end dropstations 172 a, 172 d may lack covers 220 (the left side of station 172d and the right side of station 172 a in the illustrated example). Thismay facilitate routing of the lines 214, 216 through the stations 172a-172 d. Accordingly, the stations 172 a-172 d may provide conduits orpassages through the front housing 208 to facilitate this routing.

The embodiment of FIG. 16 illustrates an alternative embodiment for thecollar 178 that includes a rectangular shape with a semicircular cutoutaround the openings 176. The collar 178 near its rear edge defines apivot 224 or hinge 224 to which a lid may attach and rotate about anaxis substantially parallel to the horizontal direction 12 c. A motormay be incorporated into the collar 178 for automatically opening andclosing the lid. A sensor may be incorporated into the collar 178 forsensing the position of the lid as positioned by a human operator, e.g.opening and closing of the list. For example, upon closing, thecontroller may receive an output from the position sensor indicatingclosing and, in response, invoke lowering of the lift arm 188 to theunlock position. Upon opening, the controller may receive an output fromthe position sensor indicating opening and, in response, invoke raisingof the lift arm 188 until the lower stack height sensor 200 b isobstructed and the upper stack height sensor 200 b is not obstructed.

The embodiment of FIG. 16 further illustrates beams 222 emitted by thesensors 200 a, 200 b. As shown the beams 222 overlap the opening 176 ofthe dish station 172 a-172 d in a plane parallel to the longitudinal andhorizontal directions 12 a, 12 c. The beams 222 of the sensors 200 a,200 b are offset from one another in the vertical direction 12 b suchthat each sensor 200 a, 200 b senses obstruction at a different verticalposition. As known in the art, a break beam sensor includes atransmitter that emits the beam 222 directed at a receiver that receivesthe beam 222 when there is no obstruction. Obstruction is thereforedetected when the receiver produces an output indicating that the beamis no longer detected. Accordingly, where the sensors 200 a, 200 b areembodied as break beam sensors, the transmitter and receiver for eachsensor 200 a, 200 b may be mounted within the collar 178 such that thetransmitter and receiver for the upper stack height sensor 200 a are ata higher vertical position along vertical direction 12 b than thetransmitter and receiver for the lower stack height sensor 200 b. Asnoted above, the sensors 200 a, 200 b may be distance sensors. Thesensors 200 a, 200 b may therefore be used to estimate a diameter of adish positioned adjacent the sensor 200 a, 200 b.

FIGS. 17 and 18 illustrate a dish drop stations 172 a-172 d having a lid230 rotatably mounted to the pivot 224. The pivot 224 may be a dampenedhinge in order to reduce damage to the lid and avoid sudden closing andopening. As shown, the lid 230 may hang over the rear side of thestation 172 a-172 d when open. The lid 230 may define openings 232 tofacilitate gripping and lifting by a user. In the illustratedembodiment, the distal end and lateral edges of the lid 230 may havesides 234 a-234 c extending downwardly therefrom and resting on the topplate 174 when the lid is closed. In such embodiments, the openings 232may be defined in one or more of the sides 234 a-24 c, such as in thesides 234 a and 234 c in the illustrated embodiment. Various otherembodiments of a lid 230 may be used. For example, the lid may beslidably attached to the collar 178 or top plate 174.

The lid 230 may define an indentation 236 for receiving additionaldinner ware stacked on it when it is closed, e.g. a circular indentationhaving a flat bottom sized to receive plate that will also fit throughthe collar 178, the indentation having a depth of between 1 and 2 cmbelow the portion of the lid 230 surrounding the indentation.

The controller may be coupled to a motor 238 controlling actuation ofthe lid 230. The controller may also be coupled to a sensor 240 thatsenses a state of the lid 230, e.g. whether the lid 230 is closed. Asensor 240 may be used that senses an angular position of the lid 230.

In some embodiments, the controller may be programmed to cause the motor238 to close the lid 230 in response to the lift arm 188 reaching thefull position when receiving dishes. The controller may be programmed tocause the motor 238 to close the lid 230 in response to the lift arm 188reaching the top position when dispensing dishes. The controller may beprogrammed to refrain from lifting the lift arm 188 in response todetecting that the lid sensor 346 indicates that the lid is closed. Thecontroller may be programmed to generate an alert if the lid sensor 240does not indicate that the lid has closed after the controller hasinvoked closing of the lid 230 by the motor 238. In some embodiments,the controller may be programmed to lower the lift arm 188 to the homeposition or the unlock position in response to sensing that the lid 230has been closed according to the lid sensor 240.

Referring to FIG. 19, in many cases, a restaurant will use dishes ofvarious sizes at the same time. Dish carts 10 may be configured toaccommodate these different sizes. The dish drop stations 172 a-172 dmay likewise be configured to accommodate differently sized dishes. FIG.19 illustrates a dish drop station 172 a with a ring 240 a positionedwithin the opening 176, the ring 240 a having a first inner diameter. Adish drop station, 172 b in this example, includes a differently sizedring 240 a positioned in its opening 176, the ring 240 b having a secondinner diameter that is less than the first inner diameter. In thismanner, users are prevented from putting dishes in the station 172 bthat are too large. The rings 240 b may rest in the openings 176, e.g.,by defining flanges that rest on the top plate 174 and prevent the rings240 a, 240 b from passing completely through the openings 176.

The rings 240 a, 240 b may be used in conjunction with the block 162 ofFIGS. 11A to 12B. In particular, a ring 240 a, 240 b and block 162 of adish drop station 172 a-172 d may be selected that correspond to oneanother such that the block 162 adjusts the adjustment assembly 110 ofcarts 10 positioned in the dish drop station 172 a-172 d such that thevans 112 a-112 c are positioned to receive dishes sized to fit throughthe selected ring 240 a, 240 b and are not positioned to receive dishes(i.e., define an unobstructed space among the vanes 112 a-112 c that istoo small to receive dishes) that are too large to fit through theselected ring 240 a, 240 b.

The rings 240 a, 240 b may also be used in cooperation with dish carts10 incorporating rails 48 sized to receive dishes passing through a ring240 a, 240 b matching the dish diameter that will fit among the rails 48as described below with respect to FIGS. 2 and 5.

FIG. 19 further illustrates the configuration of the sensors 200 a, 200b. In particular, each break beam sensor 200 a, 200 b includes both atransmitter and a receiver that are co-located and mounted in the collar178 over the opening 176. Light 222 from the transmitter of a sensor 200a, 200 b that is reflected back to the receiver of the sensor 200 a, 200b indicates obstruction and may further be used to measure a distance tothe object that reflected the light.

Referring to FIG. 20, in use the lift arm 188 may operate amongpredefined positions as controlled by the controller of the dish dropstation 172 a-172 d. In particular, the arm may begin at a home position(“Home” in FIG. 20) in which the lift arm 188 and lift paddle 190 arepositioned below the top plate 54 of a cart 10 positioned in the dishdrop station 172 a-172 d. Specifically, in the home position the liftarm 188 and paddle 190 are positioned in a gap below the top plate 54and above any front frame member 22 a or bottom plate 66. In thismanner, in the home position, the cart 10 may be inserted into the dishdrop station 172 a-172 d without the lift arm 188 and lift paddle 190interfering with the insertion. Likewise, in the home position, anydishes loaded onto the lift paddle 190 will be deposited on the pad 56and will likewise not interfere with insertion of the lift arm 188 andlift paddle 190. As discussed below with respect to FIGS. 24 through28C, in the home position, a cart will be able to latch itself into thedish drop station 172 a-172 d without requiring movement of the lift arm188.

The controller may further position the lift arm 188 in an unlockposition (“Unlock” in FIG. 20). The unlock position is slightly (e.g.,1-3 cm) below the home position and results in the lift arm 188 engagingthe cart lock 198 such that the cart lock 198 disengages from the dishcart 10. Example cart locks 198 are described below.

In some embodiments, a controller will permit automated lowering of thelift arm 188 and lift paddle 190 according to outputs of the sensors 200a, 200 b until the lift arm reaches a full position (“Full” in FIG. 20).Upon sensing movement of the lift arm 188 to this position, thecontroller will stop lowering the lift arm 188 in response toobstruction of the upper stack height sensor 200 a. For example, thecontroller may move the lift arm 188 to the home position or the unlockposition.

The controller may likewise sense arrival of the lift arm 188 at a topposition (“Top in FIG. 20). Upon sensing arrival at the top position,the controller no longer raises the lift arm 188 in response todetecting that the lower stack height sensor 200 b is not obstructed.

In some embodiments, the lid 230 may be actuated by an actuator, e.g. anelectric motor. Accordingly, the controller may be programmed to causethe actuator to close the lid 230 upon detecting arrival of the lift arm188 at the top position or the full position.

Upon reaching the full position or the top position, the controller maylower the lift arm 188 to the home position and refrain from takingfurther action until an instruction is received. For example, thecontroller may be programmed to wait until an instruction is received tolower the lift arm 188 to the unlock position, such as detectingpressing of the button 180, receiving a wireless control signal,detecting closing of the lid 230, or some other control input.

Sensing position of the lift arm 188 may be accomplished using anysensing technology known in the art, such as limit switches mounted inthe dish drop station 172 a-172 d that are triggered by the lift arm 188when located at the designated location (e.g., the full position and topposition), break beam sensors mounted in the dish drop station 172 a-172d that detect obstruction by the lift arm 188 when at the designatedlocation. Sensing of the position of the lift arm 188 may also beperformed using encoders such as hall encoders or optical encoders

FIGS. 21A and 21B illustrate use of a dish drop station 172 a-172 d incombination with a dish cart 10. As shown in FIG. 21A, a loaded orunloaded cart (unloaded in the illustrated example) is positioned withinthe dish drop station 172 a-172 d with its front edge facing the innerwall 192 and such that the lift arm 188 inserts below the top plate 154,such as in a gap between the front frame member 22 a and the lower plate66. Positioning of the cart 10 may be accomplished by rolling the cartinto the dish drop station 172 a-172 d along the longitudinal direction12 a. The lift arm 188 is positioned in the home position or the unlockposition during insertion.

The controller may then invoke raising of the lift arm 188 and liftpaddle 190 through the lobe openings 58 in the pad 56 and plate 54 andthrough the slots 60, 62. When the cart 10 is loaded with dishes 250,the lift arm 188 will rise until the lower stack height sensor 200 b isobstructed and the upper stack height sensor 200 a is not obstructedpreparatory to removing dishes 250 from the cart 10 for serving food orfor washing. The controller will then raise the lift arm 188 when thelower stack height sensor 200 b is not obstructed until either the lowerstack height sensor 200 b is obstructed or the lift arm 188 reaches thetop position.

When the cart 10 is empty, the lift arm 188 will rise to the topposition preparatory to receiving clean or dirty dishes 250. Thecontroller will then lower the lift arm 188 when the upper stack heightsensor 200 a is obstructed until the upper stack height sensor 200 a isnot obstructed or the lift arm 188 reaches the full position.

Referring to FIGS. 22 and 23, raising and lower of the lift arm 188 maybe performed using the illustrated drive mechanism that is housed withinthe front housing 208. The illustrated drive mechanism is exemplaryonly. Any translational actuator known in the art may be used forraising and lower the lift arm 188. In a like manner, any positionsensing technology known in the art may be used to sense the position ofthe lift arm 188 or to detect when the lift arm 188 is at apredetermined position (e.g., the top, full, and unlock positions).

In the illustrated embodiment, one or more rails 260 guide sliding ofone or sliders 262 mounted to the rails 260 along the vertical direction12 b. In the illustrated embodiment, the sliders 262 clamp onto therails 260. Alternatively, the rail 260 may be replaced with a verticallyoriented slot into which slider's 262 insert.

One or both of the sliders 262 is fastened to a chain 264 looped arounda lower sprocket 266 a and an upper sprocket 266 b. The upper or lowersprocket 266 a, 266 b may be driven by a motor 268 that is controlled bythe controller. The cart lock 198 is mounted adjacent the rails 260 andengages the aperture 100 on a dish cart 10 in order to hinder removal ofa cart until the lift arm 188 is in the unlock position. Variousembodiments of the cart lock 198 are described below. The cart lock 198may be located near the bottom of the travel of the lift arm 188, suchthat the cart lock 198 is unlocked when the sliders 262 are slightlyabove (e.g., 1-3 cm) a top of the lower sprocket 266 a.

As noted above, position sensors may sense when the lift arm 188 ispositioned at the top, full, or unlock positions. For example, sensors270 a, 270 b, 270 c, and 270 d may be positioned to sense when the liftarm is at positions corresponding to the unlock, home, full, and topposition, respectively as shown. The sensors 270 a-270 d may bemechanical buttons or switches positioned such that they actuated bysliders 262 or lift arm 188 as it travels along the rails 260.Alternatively, the sensors 270 a-270 d may be break beam sensors thatare obstructed by the lift arm 188 or other structure (e.g. the sliders262) coupled to the lift arm 188 as it moves to the position of thebreak beam sensor.

In other embodiments, the motor 268 is a stepper motor such or a DC(direct current) motor with an integrated absolute encoder such that itsmovement is known and may be used to infer the position of the lift arm188 and whether it is at any of the top, full, and unlock positions. Instill other embodiments, rotation of a sprocket 266 a, 266 b or themotor 268 itself is measured and used to infer the position of the liftarm 188 and whether it is at any of the top, full, unlock, and homepositions.

Referring to FIG. 24, some embodiments the sliders 262 include foursliders, two on each rail 260. The sliders 262 may fasten to a plate 278to which the lift arm 188 is fastened, such as by means of welds, bolts,or other fastening means.

FIG. 24 further illustrates an example embodiment of a cart lock 198.The cart lock 198 may interface with a pressing tab 280 that is coupledto the lift arm 188, i.e. moves vertically in unison with the lift arm188. In the illustrated embodiment, the pressing tab 280 is fastened toone of the sliders 262 and protrudes outwardly from the slider 262 inthe horizontal direction 12 c. In the illustrated embodiment, a lowersurface of the pressing tab 280 is flat and substantially parallel tothe longitudinal and horizontal directions 12 a, 12 c.

The cart lock 198 may define a pivot 282 and a lever 284 that isrotatable about the pivot 282. The pivot 282 may be fixed relative tothe housing 208, such as by fastening to the inner wall 192 of the dishstation 172 a-172 d. The lever 284 protrudes on either side of the pivot282 such that a first end of the pivot engages the pressing tab 280 whenthe lift arm 188 is lowered to the unlock position. A second end of thepivot is positioned having the pivot 282 positioned between the firstend and the second end. The second end engages a lifting rod 286 suchthat when the first end is urged downwardly by the pressing tab 280, thesecond end lifts the lifting rod 286.

In the illustrated embodiment, the lifting rod 286 passes through ahousing 288 having a return spring 290 positioned therein and encirclingthe lifting rod 286. A spring stop 292 secures to the lifting rod 286within the housing 288 and is fixed relative to the rod 286 such thatthe spring 290 engages the spring stop 292 and urges the rod 286downwardly toward a bottom wall 294 of the housing. The bottom wall 294of the housing may limit movement of the spring stop 292 when the springstop is pressed against the bottom wall 294 of the housing. The spring290 likewise engages a top wall 296 of the housing, which may beremovable to facilitate installation of the spring 290.

The lifting rod 286 extends outwardly form the top wall 296 and securesto an arm 300 protruding outwardly from the lifting rod 286, whichincludes protruding outwardly in a plane substantially parallel to thelongitudinal and horizontal directions 12 a, 12 c. A locking post 302secures to the arm 300 and protrudes downwardly therefrom offset fromthe lifting rod 286.

As shown in FIG. 25, when the lifting arm 188 and pressing tab 280 arelowered to the unlock position, the lever 284 presses upwardly on thelifting rod 286 and presses the spring stop 292 against the spring 290.This also raises the arm 300 and the locking post 302. As shown in FIG.26, as the lifting arm 188 and pressing tab 280 are raised and pressureon the lever 284 is released, the spring 290 urges the spring stop 292downwardly along with the lifting rod 286, thereby lowering the arm 300and locking post 302.

FIGS. 27A to 27D illustrate interaction of the cart lock 198 with a cart10, specifically the top plate 54 and aperture 100 of a cart 10. Notethat some carts include two apertures 100 such that a dish drop station172 a-172 d may include two cart locks 198 as described herein.

Referring specifically to FIG. 27A, a user inserts a cart 10 into thedish drop station 172 a-172 d such that the top plate 54 engages thelocking post 300. In the example of FIG. 27A, the arm 298 and 300 arelowered due to the lift arm 188 being above the unlock position, e.g.,the home position. In the illustrated embodiment, the locking post 302is provided with a beveled leading edge 304 that engages a beveledleading edge 306 of the plate 54 such that the locking post 302, arm300, and lifting post 286 are urged upwardly against the restoring forceof the spring 190, as shown in FIG. 27B. The cart 10 is pushed furtherinward such that the locking post 302 is urged to the location of theaperture 100 as shown in FIG. 27C. Upon reaching the opening 100, thelocking post 100 is urged into the opening 100 due to the restoringforce of the spring 190.

In another use case, the lift arm 188 is lowered to the unlock positionthereby raising the arm 300 to the position shown in FIG. 27C. The cart10 is then inserted such that the aperture 100 is positioned below thelocking post 302. The arm 188 is then lifted from the unlock position,which permits the spring 190 to urge the locking post 302 into theopening 100. Removal is the opposite of insertion—the lift arm 188 islowered to the unlock position, causing the arm 300 and locking post 302to rise, thereby disengaging from the aperture 100 and permittingremoval of the cart 10.

FIGS. 28A to 28C illustrate an alternative embodiment of a cart lock198. In this embodiment, an arm 310 is pivotally mounted to the fronthousing 208, such as to a pivot 312, such that the arm 310 is rotatableabout an axis substantially parallel to the horizontal direction 12 c.The arm 310 defines a lock surface 314 that faces toward a front of thedish drop station 172 a-172 d, i.e. faces away from a dish cart 10positioned in the dish drop station 172 a-172 d. Specifically, the locksurface 34 faces such that the lock surface may engage the opening 100and resist removal of the dish cart 10.

The arm 310 may further define a sloped or beveled surface 316 thatslopes downwardly with distance toward the front of the dish dropstation 172 a-172 d. The sloped surface 316 may facilitate guiding thearm 310 over the front edge of the plate 54 when inserting a cart withinthe dish drop station 172 a-172 d.

A hanging arm 318 is suspended from the arm 310 from a pivot 320 aboutwhich the hanging arm 318 is rotatable. The pivot 320 defines an axis ofrotation that is substantially parallel to the horizontal direction 12c. The pivot 312 is located on the arm 310 between the pivot 320 and thelock surface 314 such that a downward force on the hanging arm 318results in rising of the lock surface 314. The hanging arm 318 defines apressing surface 322 that protrudes outwardly from the arm 318. Thepressing surface 322 may define a surface that for at least one positionaround the pivot 320 is substantially-parallel to the longitudinal andhorizontal directions 12 a, 12 c.

In use, when the lift arm 188 is moved to the unlock position (see FIG.28C), the lift arm 188 rests on the pressing surface 322, thereby urgingthe locking surface 314 upward and ready to receive a dish cart 10.When, the lift arm 188 is raised, the locking surface 314 pivotsdownward into the opening 100. This may be facilitated by gravity. Inparticular, the pivot 320 may be closer to pivot 312 such that theweight of the arm 310 on the opposite side of the pivot 312 issufficient to overcome the weight of the hanging arm 318. In otherembodiments, the arm 310 may be spring loaded such that it is urged intothe position shown in FIG. 28B in the absence of force on the pressingsurface 322.

Referring to FIG. 29, in some embodiments, a dish drop station 172 a-172d may include additional or alternative means for retaining a dish cart10. For example, one or more ferromagnetic lugs 96 may secure to one orboth front vertical posts 40 a, 40 b of a dish cart 10, such asaccording to the embodiment of FIG. 5. One or two magnetic detents 330may mount to the inner wall 192 of the dish drop station 172 a-172 d andbe positioned to engage the one or two lugs 96 when the cart ispositioned in the dish drop station 172 a-172 d, i.e. exert a certainamount of pull on the lug 96, such as a force at least 3 to 20 Newtonswhen the cart 10 is pushed to its inwardmost position within the dishdrop station 172 a-172 d.

In some embodiments, the controller of the dish drop station 172 a-172 dmay be coupled to a cart present sensor 332 that detects whether a cart10 is positioned within the dish drop station 172 a-172 d. For example,the cart present sensor 332 may be an inductive sensor that can detectthe metal vertical posts 40 a or 40 b of a cart or other metal portionof the cart 10. In particular, the sensor 332 may be an inductive sensorpositioned within a plastic housing (e.g., non-inductive, non-glassfilled) yet able to sense metal positioned proximate the sensor 332outside of the housing. Other types of sensors 332 may be used, such asa break beam sensor that is obstructed by the cart 10, a mechanicalbutton or switch actuated when the cart 10 is inserted into the dishdrop station 172 a-172 d, or some other type of sensor.

In some embodiments, if the controller receives an output from thesensor 332 that indicates that no cart 10 is present, the controller maybe programmed to wait for a delay period followed by moving the lift arm188 and paddle 190 to the home position if not already at the homeposition. In other embodiments, the controller prevents all movement ofthe lift arm 188 when no cart 10 is sensed as being present

If the cart present sensor produces an output indicating a transition toa cart 10 being present, the controller may be programmed to raise thelift arm 188 from the home position until one of the following is true:(a) the lower stack height sensor 200 b is obstructed while the stackheight sensor 200 a remains unobstructed (the cart 10 was loaded withdishes) or (b) the lift arm 188 reaches the full position (the cart 10was empty and ready to be loaded).

Referring to FIG. 30, references to a controller hereinabove may beperformed by a controller 340 performed to perform those functions. Thecontroller 340 may be embodied as a general purpose computer or adedicated circuit programmed to perform the functions ascribed to thecontroller hereinabove. In particular, the controller 340 may controlsupply of power from the power supply 218 supplied to the lift motor 268according to outputs received from some or all of the on/off switch 180,upper and lower stack height sensors 200 a, 200 b, the emergency stopbutton 210, reset button 212, the unlock position sensor 270 a, the homeposition sensor 270 b, the full position sensor 270 c, the top positionsensor 270 d, and the cart present sensor 332.

In addition, the controller 340 may be coupled to a transceiver 342,such as a WI-FI transceiver, BLUETOOTH transceiver, or other type ofwireless transceiver. As noted above, the antenna for the transceiver342 may be mounted within the plastic collar 178. The controller 340 maybe programmed to receive instructions through the transceiver 342 from acentral controller or to transmits its state to a central controller.For example, the controller 340 may transmit a notification when thelift arm 188 reaching the full position, indicating that a cart 10 fullof dirty dishes needs to be removed and replaced with an empty cart. Thecontroller 340 may transmit a notification when the lift arm 188 reachesthe top position, indicating that a cart 10 is empty of dishes and needsto be replaced with a cart 10 full of clean dishes. The controller 340may transmit other information, such as a rate of rise or fall of thelift arm 188, which may be used to estimate when it will be empty orfull, respectively, enabling preemptive preparation of a full or emptycart, respectively.

The controller 340 may transmit a notification in response to detectionof a malfunction, such as sticking of the lift arm 188, which may bedetected by the lift arm failing to move to a desired position (top,full, unlock) in response to the controller 340 instructing the motor268 to move the lift arm 188 to the desired position.

The controller may transmit a notification upon detecting interactionwith the button 180, e.g., a notification indicating that humanattention at the dish cart station 172 a-172 d is required. For example,a user may push button 180 to indicate that a cart has been filled orempty and another empty or full cart, respectively, is needed.

While various embodiments of the present disclosure have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation. It will be apparent to persons skilledin the relevant art that various changes in form and detail can be madetherein without departing from the spirit and scope of the disclosure.Thus, the breadth and scope of the present disclosure should not belimited by any of the above-described exemplary embodiments, but shouldbe defined only in accordance with the following claims and theirequivalents. The foregoing description has been presented for thepurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure to the precise form disclosed.Many modifications and variations are possible in light of the aboveteaching. Further, it should be noted that any or all of theaforementioned alternate implementations may be used in any combinationdesired to form additional hybrid implementations of the disclosure.

What is claimed is:
 1. A cart for transporting stacked dishes, the cart comprising: a base structure that defines a slot and a plurality of lobe openings, the slot and plurality of lobe openings configured to permit passage of a lift paddle of a dish drop station in which the lift paddle includes lobes at positions that correspond to positions of the lobe openings, and wherein the slot is configured to permit passage of a lift arm of the dish drop station past a first edge of the base structure; a plurality of wheels connected to the base structure; and a push handle connected to the base structure; a plurality of spacers connected to the base structure, each spacer extending inwardly such that inward facing surfaces of the plurality of spacers define an area sized to receive stacked dishes; wherein the slot and the plurality lobe openings define a contiguous opening in a horizontal support surface of the base structure; wherein the first edge of the base structure is a front edge of the base structure, wherein the push handle is connected at a back edge of the base structure, which is opposite the front edge of the base structure; and wherein the base structure includes an aperture configured to engage with a cart lock of the dish drop station.
 2. The cart of claim 1, wherein the plurality of lobe openings extend out from the slot.
 3. The cart of claim 1, wherein the plurality of spacers comprises a plurality of vertical spacers connected to the base structure perpendicular to the horizontal support surface of the base structure, each spacer extending inwardly to a center of the horizontal support surface such that inward facing surfaces of the plurality of spacers define an area sized to receive the stacked dishes.
 4. The cart of claim 1, wherein the aperture is located closer to the front edge of the base structure than to any other edge of the base structure.
 5. The cart of claim 4, wherein the front edge of the base structure is beveled to engage an element of the cart lock.
 6. The cart of claim 4, wherein the aperture is in the horizontal support structure of the base structure.
 7. The cart of claim 1, wherein the aperture is in the horizontal support structure of the base structure.
 8. A cart for transporting stacked dishes, the cart comprising: a base structure that defines a slot and a plurality of lobe openings, the slot and plurality of lobe openings configured to permit passage of a lift paddle of a dish drop station in which the lift paddle includes lobes at positions that correspond to positions of the lobe openings, and wherein the slot is configured to permit passage of a lift arm of the dish drop station past a first edge of the base structure; a frame connected to the base structure; a plurality of wheels connected to the base structure; and a push handle connected to the base structure; a plurality of spacers connected to the frame, each spacer extending inwardly to a center of the frame such that inward facing surfaces of the plurality of spacers define an area within the frame that is sized to receive stacked dishes; wherein the plurality of lobe openings extend out from the slot and wherein the slot and the plurality lobe openings define a contiguous opening in a horizontal support surface of the base structure; wherein the first edge of the base structure is a front edge of the base structure, wherein the push handle is connected at a back edge of the base structure, which is opposite the front edge of the base structure; and wherein the base structure includes an aperture configured to engage with a cart lock of the dish drop station.
 9. The cart of claim 8, wherein the plurality of spacers comprises a plurality of vertical spacers connected to the frame and perpendicular to the horizontal support surface of the base structure, each spacer extending inwardly to a center of the frame such that inward facing surfaces of the plurality of spacers define an area sized to receive the stacked dishes.
 10. The cart of claim 8, wherein the aperture is located closer to the front edge of the base structure than to any other edge of the base structure.
 11. The cart of claim 10, wherein the front edge of the base structure is beveled to engage an element of the cart lock.
 12. The cart of claim 10, wherein the aperture is in the horizontal support structure of the base structure.
 13. The cart of claim 8, wherein the aperture is in the horizontal support structure of the base structure. 